Supernova
A supernova is the explosive death of a star, during which it rapidly ejects most of its mass in a brilliant burst of light. In core‑collapse supernovae (Types Ib, Ic, II), massive stars (≥ 8 solar masses) exhaust their nuclear fuel, collapse under gravity, and explode. In Type Ia supernovae, a white dwarf in a binary system undergoes runaway fusion after accreting mass. These events deliver heavy elements into space, leave behind neutron stars or black holes, and power typical shock‑front supernova remnants.
Source: heasarc.gsfc.nasa.gov
APODs including "Supernova"
X-Rays From Antennae Galaxies
18/08/2000
A bevy of black holes and neutron stars shine as bright, point-like sources against bubbles of million degree gas in this false-color x-ray image from the orbiting Chandra Observatory. The striking picture shows the central regions of two galaxies, NGC 4038 and NGC 4039, locked in a titanic collision some 60 million light-years distant in the constellation Corvus. In visible light images, long, luminous, tendril-like structures emanating from the wreckage lend the pair their popular moniker, the Antennae Galaxies. Galactic collisions are now thought to be fairly common, but when they happen individual stars rarely collide. Instead gas and dust clouds merge and compress, triggering furious bursts of massive star formation with thousands of resulting supernovae. The exploding stars litter the scene with bubbles of shocked hot gas and collapsed stellar cores. Transfixed by this cosmic accident astronomers watch and are beginning to appreciate the collision-driven evolution of galaxies, not unlike our own.